Process for preparing mixed esters from phenolaldehyde resins



use of linolic acid it was found for instance that Patented July 19,1938 PATENT OFFICE FROM PHENOLALDEH'YDE RESINS PROCESS FOR PREPARINGMIXED ESTERS Hans Theodor Bucherer, Munich, Germany No Drawing.Application April 6, 1935, Serial No.

15,092. In Germany April 13, 1934 3 Claims.

It is known that various kinds of phenol-alde- 'hyde resins, i. e.,novolak, resol and resite may be converted into new valuable compoundsby.

closing or tying up the hydroxyl groups (see German Patent Number391,072), and that among the materials suitable for'preparing valuableester-like derivatives of such resins are certain carboxylic. acids ofhigh molecular weight (see German Patent Number 456,820). Suchcarboxylic acids are, for example, stearic acid,

. palmitic acid, oleic acid, and the acid of colophony, sometimes knownas abietic acid.

It has been found that when certain other carboxylic acids of highmolecular weight are used, the melt gradually loses its homogeneityunder the high temperature which is required for the esterification, andthat undesirable.

gummy substances, which are completely or almost completely insoluble inthe usual solvents, are precipitated at an increased rate. Thiscondition applies, especially when it is attempted to use linolic acid.The gummy substances formed by such attempts at esteriflcation are,because of a lack of suflicient solubility, not suitable for immediateuse in the manufacture of paints or the like.

Now it has been found that sufliciently soluble ester-like compounds ofresins adapted for widely varied purposes, are obtained by esterifyingthe. resins with mixtures of carboxylic acids, the proportions of theindividual acids in the mixtures being such that no gummy substances areformed or, if formed, are inappreciable. The ratio in which suchmixtures are to be used, must be tried out in every single case. Withthemixtures of colophony and linolic acid even in the ratio of 3:7, thatis, three parts of colophony to seven parts of linolic acid, result inthe production of mixed esters the solubility of which still meets theordinary-demands completely. If

the proportion of the linolic acid is increased considerably in excessof the ratio indicated, the

3;.7 readily soluble esters of suillciently high melting-point areobtained.

These mixed esters containing linolic acid as. a component areparticularly valuable because of .their surprising behaviour in thedrying process. Even without the use of siccative, coats of paintsproduced with the aidof these mixed 5 esters surpass in drying power allknown painting-agents, as afterbut a few hours a dry film is producedsuch as may not be expected before a day or two with the use of theusual linseedoil varnishes.

.Another surprising feature of equally great practical importance is thefact that the film which forms during the drying is' capable ofundergoing alterations under the influence of air and light such asthose occurring with the ordi-' 15 nary linseed-oil films and whichmanifest themselves particularly in a change of their solubility, i. e.,the esters forming the film and previously soluble become vmore or lessinsoluble in the usual solvents even after a short time.

What I claim is:

1. The herein described process oi preparing a rapid-drying mixed esterdevoid of gumminess and having suflicient solubility for use as aningredient of paint, which consists in esterifying 25 v a phenolaldehyderesin with a mixture of linolic acid and colophony in the approximateproportions of seven .parts of linolic acid to three partsof colophony.

2. The ,herein described process of producing a so rapid-drying mixedester substantially devoid of gumminess and sufllciently soluble for useas an ingredient of paint, which process consists in esterifying aphenolaldehyde resin with a mixture of carboxylic acids, said mixturecontaining linolic acid and a second acid of high molecular weightselected from the class consisting of colophony, stearic acid. palmiticacid and oleic acid, the proportion of the linolic acid to said secondacid being approximately 7 to 3. o

3. A compound consisting of the product of esteriflcation of aphenol-aldehyde resin with a. mixture of linolic acid and asecondcarboxylic acid selected from the class consisting of colophony,stearic acid, palmitic acid and oleic acid, the proportion of thelinolic acid to said second acid being approximately 7 to 3.

HANS THEODOR BUCHERER.

